Oily Fingers Could Give Away Your Smartphone Password

Your greasy fingers could be doing more than smudging your touchscreen: you could be tracing the path to your smartphone's password, security researchers report.

"Touchscreens are touched, so oily residues, or smudges, remain on the screen as a side effect," the report said. "Latent smudges may be usable to infer recently and frequently touched areas of the screen - a form of information leakage."

The researchers tested Android handsets because the Google OS uses a graphical password, with users tracing a pattern on the phone to unlock the device. In ideal lighting conditions, the researchers managed to decipher the phone's password 92% of the time by taking photos of the screen and bumping up the contrast.